88 ANNUAL OF SCIENTIFIC DISCOVERY. 



more brittle and steely. After this the whole mass is thoroughly 

 puddled, and it comes out the best refined iron. Scrap-iron has been 

 mixed with cast-iron before, but this smelting of the mass in the pud- 

 dling-furnace is an improvement. 2. Another plan is to introduce the 

 scrap malleable iron into the puddling-furnace, and then to run in the 

 molten cast-iron from the smelting-furnace, before the scrap-iron is 

 thoroughly smelted. The smelted iron has before been run directly in- 

 to the puddling-furnace, but not mixed with the scrap in this manner. 

 The inventor states that one fifth of scrap mixed with rich pig iron pro- 

 duces an article of iron of great ductility and fibrousness, which may be 

 readily worked under the hammer or between the rolls. For tires of 

 wheels and the surfaces of rails, the scrap-steel mixed with the cast- 

 iron is a great improvement. By mixing one hundredth part of block- 

 tin with the cast and scrap iron in the puddling-furnace, he produces a 

 metal of smooth exterior, very hard, but which can be wrought by the 

 hammer or rolls. The addition of zinc or its oxides in the puddling- 

 furnace produces a bright-colored metal with a clean surface, which is 

 very ductile and fibrous. To make a hard, steely iron, suited for 

 wheel-tires and rails, he introduces black oxide of manganese into the 

 puddling-furnace, mixing it well with the metal. 



TO ENAMEL IRON. 



THE best and latest process for this purpose is the following. The 

 articles to be enamelled should be first thoroughly cleansed, and then 

 they are ready to receive the first coat, which is made of 100 parts of 

 calcined flint, ground to a fine powder, mixed with 75 parts of fine- 

 grained borax. This mixture is fused together, and when cooled is 

 ground with 22 parts of potter's clay in water until it is of such con- 

 sistency that, when an article to be glazed is dipped into it, a coating of 

 about one sixth of an inch is retained. After this is done, the article 

 is put on one side to allow the composition to " set," as it is technically 

 called. But while it is yet moist, a composition containing 100 parts 

 of cornish-stone, or red limestone, ground fine, 117 parts of borax, also 

 pulverized, 35 of soda-ash, 35 of saltpetre, 35 of sifted lime, 50 of 

 white glass, well pounded, and 13 of white sand, is carefully sifted 

 over the surface to produce the glaze. These materials must be well 

 mixed and burned in a crucible, and when cool, ground to a fine pow- 

 der, after which they should be washed and dried. About 45 parts of 

 them are mixed with one part of soda-ash in hot water, being well 

 stirred together and then dried in the oven. The mixture is then 

 ready for use. After the articles have been dusted over with this, 

 they are placed in the oven of a stove, and kept at a temperature of 

 212 till the composition is dry, when they are placed in a kiln or muf- 

 fle, and submitted to a sufficient degree of heat to fuse the glaze. If 

 the glazing is not found perfect all over, the articles can be moistened 

 with salt and water, and v the glazing-powder sifted over them again, 

 after which they must be subjected to the heat of the kiln again. 

 Scientific American. 



